Guide device for wire rod

ABSTRACT

A device particularly for guiding wire rod leaving a rolling mill in horizontal direction and directed to a coiler of vertical axis. The device comprises a first disc provided with a peripheral groove, the disc being movable in contact with the wire rod along a substantial portion of the path thereof, having substantially its peripheral speed equal to the advancement speed of the wire rod. A second rotatable disc is provided tangential to the first disc at the point of exit of the wire rod from the first disc. The device is further provided with a unit for synchronising the speeds of the first disc and the second disc with the speed of the wire rod. The speed synchronising unit principally comprises a transmission unit of gear wheel type which has the same number of speed steps as the number of advancement speeds provided for the wire rod.

United States Patent l i 11 3,906,772 Properzi 1 Sept. 23, 1975 GUIDE DEVICE FOR WIRE ROD {76] Inventor: Giulio Properzi, Via Pietro Cossa l, M' f 3 Milan lmly 20122 Attorney, Agent, or F|rmG. Modiano, A. Jostf [22] Filed: Nov. 19, 1973 57 ABSTRACT [21] Appl. No: 417,343 A device particularly for guiding wire rod leaving a rolling mill in horizontal direction and directed to a coiler of vertical axis The device comprises a first disc [52] 72/25; 226/! 77; 226/176 provided with a peripheral groove, the disc being mov- [5H 8218 39/20 able in contact with the wire rod along a substantial [58] he d of Search 72/251 portion of the path thereof, having substantially its pe- 226/18 ripheral speed equal to the advancement speed of the 242/79 82 wire rod A second rotatable disc is provided tangential to the first disc at the point of exit of the wire rod [56] References cued from the first disc. The device is further provided with UNITED STATES PATENTS a unit for synchronising the speeds of the first disc and 2,136,7l4 ll/l938 Simons 72/183 X the second disc with the speed of the wire rod The 2,959,334 ll/l960 Uritis 226/176 speed synchronising unit principally comprises a trans- 3-l72i99l 3/l965 22677 UX mission unit of gear wheel type which has the same groenwegenl number of speed steps as the number of advancement opper et a i l 4 1599.391 8/l97l Stone 242/32 speedh prm'ded for the 3.645,] 20 2/1972 Lind et al. 72/l 34 4 Claims, 4 Drawing Figures Sept. 23,1975 Sheet 1 of 3 US Patent US Patent Sept. 23,1975 Sheet 2 Of3 3,906,772

US Patent Sept. 23,1975 Sheet 3 of 3 3,906,772

GUIDE DEVICE FOR WIRE ROD This invention relates to a guide device for wire rod at the outlet of a rolling mill. In particular the device is provided for rolling mills in which the wire rod leaving the last rolling stand is directed towards a coiler the purpose of which is to form coils which are subsequently cooled and then conveyed to a device for forming skeins or similar finished items.

The wire rod leaves the rolling mill with its axis substantially horizontal whereas the coiler, for reasons of space and especially for operating reasons, for example to enable the wire rod coils to be cooled in a cooling bath, is of substantially vertical axis. The hot wire rod must consequently be deviated and this has been done up to the present time by means of a tube having a curvature of large radius, a reason being because a tube lends itself well to the preliminary cooling of the wire rod before it reaches the coiler. But this solution gives rise to various disadvantages.

When the wire rod which leaves the rolling mill is de viated at a speed V along a trajectory of radius R, each element of mass m of the wire rod is subjected to a centrifugal force I]. m R

This centrifugal force becomes larger as the outlet speed V increases and the radius of curvature R decreases. Under the action of the centrifugal force the wire rod is thrust against the wall of the guide tube and braking friction forces arise which are directly proportional to the centrifugal force F,., and which on the one hand ruin the surface of the wire rod which was finished in the last rolling stand and on the other hand slow down the movement of the wire rod, which however continues to emerge at an unchanged speed from the last rolling stand. A situation arises in which the wire rod, which resembles a rod loaded at its point between the outlet of the last rolling stand and the guide tube with which it is in contact, and which is moreover composed of metal at high temperature under very low resistance conditions, soon undergoes buckling in the guide tube under the thrust action of the wire rod upstream, with the final result that the guide tube becomes blocked, with disastrous consequences for the rolling plant.

This phenomenon is particularly grave when in order to obtain sufficiently high hourly production the outlet speed is high, for example of the order of 40-50 m/sec, as it is possible to obtain today at the outlet of a rolling mill. In this case any rubbing against the inner wall of the guide tube is able to produce this buckling. The sit uation is still more critical when small diameter rod is to be produced, for example 3-4 mm, as is today required to an increasingly greater extent by the market.

It is clear that a rod of this diameter, for like speeds and all other temperature and consistency conditions, is still less resistant to buckling.

A satisfactory solution to these problems has not yet been found. In general the coiler tends at present to be placed at a large distance from the rolling mill so as to be able on the one hand to partially cool the rod so as to give it greater strength and to be able on the other hand to follow a trajectory with a large radius of curvature. But this means that the entire equipment becomes extremely bulky without resolving the problem.

When the diameter of the wire rod is in the order of 3-4 mm and the outlet speeds have to be very high because of production requirements, i.c. more than 40 m/sec, this disposition becomes itself critical, independently of the size of the equipment.

The fundamental object of the present invention is to provide a guide device for wire rod at the outlet of a rolling mill, which by overcoming the disadvantages and limitations of known systems enables the rod to be guided and deviated even under conditions of high temperature and speed without damaging its surface and without any danger of buckling arising, thus eliminating the already mentioned consequences for the rolling mill.

A further object of the invention is to provide a guide device of such a structure as to protect the rod, if necessary, from contact with air so as to avoid its oxidation until it has been sufficiently cooledv A further object of the invention is to provide a device of the aforementioned type which enables the coiler to be disposed close to the outlet of the rolling mill so as to reduce the longitudinal dimension of the rolling equipment.

These and further objects which will be more evident from the description given hereinafter are attained by a guide device for wire rod at the outlet of a rolling mill, particularly of the type including a coiler for coiling the rod, comprising guide means between said outlet and said coiler, which, along at least a portion, are movable together with said wire rod at a speed substantially equal to that of the wire rod over said portion.

Further details and advantages of the invention can be deduced from the detailed description given hereinafter of a preferred but not exclusive embodiment of the guide device according to the invention, illustrated by way of example in the accompanying drawings in which:

FIG. 1 is a diagrammatic lateral view of the device according to the invention disposed between the rolling mill and the coiler;

FIG. 2 is a detail of the device shown in FIG. I to an enlarged scale;

FIG. 3 is a section on the line Ill-III of FIG. 2; and

FIG. 4 is a partially sectional view from above of the device according to the invention and the rolling mill with which the device is combined.

The device 1 according to the invention is disposed at the outlet of a rolling mill 2 for wire rod, comprising a plurality of rolling stands 3 removably mounted on guides 4 arranged on a base 5. Between one stand 3 and the next there is a seal 6 of the type described for example US. Pat. Nos. 3,668,911 and 3,805,568 the purpose of which is to ensure that the rod is guided over the entire rolling path out of contact with air, namely in a cooling and/or lubricating liquid present in the stands 3 and seals 6. It is however also possible to en close the entire rolling mill 2 in a protection housing 7.

The device 1 is supported by an extension (not shown) of the base 5 above a tank 8 containing for example a cooling liquid 9, in which the rod 10 is deposited in the form of coils from the rotating coiler II, also supported by the extension of the base 5.

The rotating coiler l] is of known type, for example of the Edenborn" type and is described here only in its main points. It is disposed with its axis vertical and is surrounded by a bell shaped housing 12 the lower part of which is immersed in the liquid 9 so as to form a seal for preventing contact between the rod and the air. The coiler is mounted particularly on the support 13 by way of the bearings 14 and 15 and receives its rotatory motion by way of gears 16 from a motor, not shown, which is also disposed on the support 13. The entry to the coiler is indicated by the reference numeral 17, and is conical in order to facilitate the entry of the rod 10 into the coiler 11. By the rotation of the coiler and the forward movement of the rod, the rod becomes arranged in coil turns and is discharged into the tank 8.

The device 1 according to the invention is positioned between the outlet of the rolling mill 2, from which the rod exits in a horizontal direction, and the coiler 11, into which the rod enters in a vertical direction, and thus acts as a deviator. It consists substantially of guide means 18 extending along at least an areuate portion of the path of the wire rod 10 and movable in contact therewith at a speed substantially equal to that of the rod itself.

In the example shown, these guide means comprise a rotatable guiding disc 19 comprising a peripheral groove 20 (FIG. 3) of substantially semicircular cross section having a diameter corresponding to that of the rod which is to be guided. The radius of the rotatable disc 19 corresponds to the radius of curvature or deviation provided for the rod and the peripheral speed of the disc 19, which is driven by driving means which will be described hereinafter, is equal or slightly greater than the outlet speed of the rod. In this manner there is no slip between the disc and the rod or at most there is a slight traction effect and the finished surface of the rod is in no way ruined. The disc i9 is arranged at such a manner that the inlet point in which the rod comes into contact with the disc is tangential to the direction of exit of the rod from the rolling mill, and the point of abandonment at which the rod leaves the disc is tangential to the axis of the rotating coiler 11. The rod consequently does not undergo any deviation other than that due to the disc 19, which is however perfectly controlled and takes place without relative motion between the rod and the guide disc.

With the guide disc 19 there is associated a second rotatable disc 21 of smaller diameter, also comprising a groove 22 corresponding to the groove 20 of the disc 19. Advantageously, this second disc 21 is disposed at the point of discharge of the rod 10 and is tangential to the disc 19. The rod 10 remains engaged between the two discs 19 and 21 at their point of tangency, and as the disc 21 is driven with the same peripheral speed as the disc 19, the rod advantageously leaves the two discs tangentially without undergoing deviation towards the one or other and is thus positioned exactly in the direction of the axis of the coiler ll.

The second disc 21 is suitably rotatably arranged on a support 23 radially movable with respect to the disc 19 within a guide element 24 fixed to the frame of the device 1. The movement of the support 23 may be mechanical as shown, in which case it advantageously takes place by the action of a threaded sleeve 25 operable by a handwheel or the like 26 and engaged with the threaded rod 27 of the support 23, so that the rotation of the handwheel or the like 26 moves the support backwards or forwards radially to the disc 19. In order to reach the handwheel or the like 26, means of access not shown in FIG. 1 will be obviously provided The movement can however also take place in other ways, for example by a spring or pneumatically or hydraulically by means of a cylinder-piston unit. The purpose of the movement of the disc 21 with respect to the disc 19 is to permit a certain adjustment of the distance between the two discs so as to obtain a determined passage cross-section between them.

In order to ensure exact synchronism between the speed of rotation of the two discs 19 and 21 and the outlet speed of the rod 10 from the rolling mill 2, kinematic transmission members such as gears, chains or toothed belts are provided, which take their motion from the last rolling stand 3 or from one of the drive shafts of any rolling stand 3 in the case ofa single block multi-stand rolling mill, and transmit it to the shafts 28 and 29 of the discs 19 and 21 in the appropriate ratios. It is however also possible to drive the two discs 19 and 21 by a separate motor coupled and synchronized electrically with the drive motor for the rolling mill.

FIG. 4 shows the case of mechanical transmission for said synchronism, particularly suitable for a multistand single block rolling mill, in which rod of different diameters can be collected from different stands by removing the last of the stands each time in order to collect rod of greater diameter from the previous stand and so The individual rolling stands 3 are driven in the usual manner by the gear chain 30 indicated diagrammatically in FIG. 4, which receives its motion from a drive motor or motors (not shown) for the rolling mill. The movement derived from one of the shafts 31 of a stand 3 is transmitted through bevel gears 32, shaft 33 and the successive bevel gears 34, to the shaft 35 which rotates in the fixed frame of the device I. On the shaft 35 are keyed the same number of gear wheels 36 as the number of speed steps which it is required to obtain. and which engage with the same number of gear wheels 37 idle on the shaft 28 which drives the disc 19. Transmission wheels 38 and 39 are keyed in a movable but rotationally rigid manner on the shaft 28, and are provided to engage with the pawls 40 of the gear wheels 37 and so establish the rotational connection between a corresponding one of these wheels and the shaft 28. The gear wheels 36 and 37 and the transmission wheels 38, 39 constitute a gearbox, the gear wheels 36 and 37 being calculated with regard to their number of teeth in such a manner as to transmit speeds to the shaft 28 which, taking into account the diameter of the disc 19, cause this latter to have a peripheral speed equal or slightly greater than the outlet speed of the rod from the last stand. Thus, on removing one stand, the gearbox is operated so as to give a speed to the disc 19 corresponding to that of the last of the remaining stands. The assembly 41 of gear wheels serves to give the correct speed also to the disc 21 in relation to that assumed each time by the disc 19, so that both have the same peripheral speed. By these means an exact synchronism is guaranteed, even during the acceleration and deceleration stages of the rod leaving the rolling mill.

Advantageously a guide 42 in the form of an arc of a circle concentric with the disc 19 is associated externally with the disc 19, and extends practically along the entire path of deviation of the rod, at a certain distance from the periphery of the disc 19. Its purpose is to deflect the head of the rod leaving the rolling mill so as to direct it along the disc 19 until the point at which the rod becomes engaged between the two discs 19 and 21, after which it is kept adhering to the disc 19 and no longer comes into contact with the guide 42, and therefore does not slide against it. The guide 42 acts only as an entry guide for the head of the rod leaving the rolling mill and its function automatically ceases as soon as the head of the rod is engaged between the two discs 19 and 21.

The initial sliding ofjust the head portion of the rod does not create problems of the type indicated initially, because the head of the rod is always at a much lower temperature than that normally assumed by the remainder of the rod leaving the rolling mill and hence does not produce buckling, at least over the first portion of about 1 meter in length.

Advantageously the entire device 1 according to the invention may be enclosed in a protection housing 43 to prevent the rod from coming into contact with the air, the housing 43 forming a complete seal between the rolling mill outlet, where a short portion of guide may be provided if the rolling mill is not enclosed in the housing 7, and the coiler l l, which in its turn is already advantageously protected by the bell housing 12 immersed in the liquid 9 of the tank 8. Thus it is possible to collect hot rod without the danger of oxidation and to cool it in the liquid 9 until it has reached a tempera ture lower than the oxidation temperature. Suitable means are provided in the tank 8 for conveying the coils formed by the coiler ll out of the tank when the rod is sufficiently cold.

Along the path of the rod upstream and downstream of the disc 19 there may also be provided short straight lengths of guide for cooling and/or lubrication and/or protection purposes, for which the same emulsion can be used as that employed for rolling.

From the description given it can be seen that with the device according to the invention any sliding of the rod with the corresponding slowing down and its tendency to buckle is avoided, while the action of the centrifugal force, which would tend to separate the rod from the disc l9 and cause it to slide against the fixed guide 42, is neutralized by the traction action exerted on the rod at the point of tangency between the discs 19 and 21.

The device described gives not only a guided deviation action for the rod but may also act as a finishing unit such as a final gauging stand of a rolling mill, for example of the single block multi-stand type such as that described in U.S. Pat. No. 3,646,790.

The device may also exercise a slight traction on the rod leaving the rolling mill and thus constitute a unit for extraction from the rolling mill and for feeding to the coiler, providing a thrusting effect to the rod fed to the coiler.

Using the device described it has been possible to deviate rod of diameter 3-4 mm at a temperature of 400500C at a speed of 4050 m/sec and beyond. along trajectories of radius 300-500 mm without difficulty and without damaging its surface. The device finds advantageous application in particular both for steel and copper rod.

The invention is susceptible to numerous modifications all of which fall within the scope of the inventive idea as defined by the following claims.

I claim:

1. A device for guiding hot wire rod at the outlet of a rolling mill from which the wire rod comes out in a substantially horizontal direction to a coiler having an axis forming an angle with said substantially horizontal direction, the device comprising movable guide means arranged between the rolling mill outlet and the coiler and contacting the wire rod along at least an arcuate path thereof extending tangentially to said substantially horizontal direction and said axis, and means for driving said movable guide means in contact with the wire rod at a spead substantially equal to that of the wire rod between the rolling mill outlet and the coiler, wherein said guide means include at least one peripherally grooved guiding disc having a radius substantially equal to the radius of curvature of said arcuate path and at least a second rotatable disc having a peripheral groove and a radius substantially less than that of said guiding disc. said second disc being arranged substantially tan gential to said guiding disc and being rotated at a pcripheral speed substantially equal to that of said guiding disc.

2. A device as claimed in claim 1, in which said guiding disc is arranged tangentially to the direction of exit of the wire rod from the rolling mill and to the direction of the axis of the coiler.

3. A device as claimed in claim 1, further comprising a unit for synchronising the peripheral speed of said guiding disc and said second disc with the outlet speed of the wire rod coming out of the rolling mill, said unit including transmission means between the driving means of the rolling mill and said discs, said transmission means including a gearbox for providing a number of a peripheral speeds for said discs as the number of outlet speeds provided for the wire rod coming out of the rolling mill.

4. A device as claimed in claim 1, comprising driving means for driving said guiding disc and said second disc at a peripheral speed slightly greater than the outlet speed of the wire rod coming out of the rolling mill. 

1. A device for guiding hot wire rod at the outlet of a rolling mill from which the wire rod comes out in a substantially horizontal direction to a coiler having an axis forming an angle with said substantially horizontal direction, the device comprising movable guide means arranged between the rolling mill outlet and the coiler and contacting the wire rod along at least an arcuate path thereof extending tangentially to said substantially horizontal direction and said axis, and means for driving said movable guide means in contact with the wire rod at a spead substantially equal to that of the wire rod between the rolling mill outlet and the coiler, wherein said guide means include at least one peripherally grooved guiding disc having a radius substantially equal to the radius of curvature of said arcuate path and at least a second rotatable disc having a peripheral groove and a radius substantially less than that of said guiding disc, said second disc being arranged substantially tangential to said guiding disc and being rotated at a peripheral speed substantially equal to that of said guiding disc.
 2. A device as claimed in claim 1, in which said guiding disc is arranged tangentially to the direction of exit of the wire rod from the rolling mill and to the direction of the axis of the coiler.
 3. A devicE as claimed in claim 1, further comprising a unit for synchronising the peripheral speed of said guiding disc and said second disc with the outlet speed of the wire rod coming out of the rolling mill, said unit including transmission means between the driving means of the rolling mill and said discs, said transmission means including a gearbox for providing a number of a peripheral speeds for said discs as the number of outlet speeds provided for the wire rod coming out of the rolling mill.
 4. A device as claimed in claim 1, comprising driving means for driving said guiding disc and said second disc at a peripheral speed slightly greater than the outlet speed of the wire rod coming out of the rolling mill. 